The invention relates to exhaust systems for internal combustion engines, including for emission control.
Exhaust systems for internal combustion engines typically include an exhaust conduit conducting exhaust gas from the engine through a catalyst. It is known to inject air into the exhaust system upstream of the catalyst. The injection air is provided by an air injection pump and supplied through a regulator valve which in turn is controlled by an oxygen sensor in the exhaust conduit.
The present invention arose during continuing development efforts relating to the above technology, and provides improvements in simplification, cost reduction, and elimination of components.